EDIT LINE

This function allows the user to edit lines.

After selecting a line, the program will display CURVE EDIT dialog box, as shown in Figure 5.1.25.

Figure 5.1.25  Curve Edit dialog box

There are four options available in this dialog box.

1.         EDIT

     This function edits lines by editing points on the selected lines. Figure 5.1.25 shows the options for editing lines.

     ADD POINT

     If this option is selected, BY CURSOR and BETWEEN 2PTS buttons are activated.

     The user can select BY CURSOR button to pick any point on the line to add.

     If BETWEEN 2PTS button is selected, the user can click the selected line by cursor directly or click Select Point button. The program will display control points on the line and prompt the user to select two adjacent points. After selection of these two adjacent points, the POINT NUMBER window will be activated to prompt the user to enter the point number between two adjacent points. If the selected second point is not adjacent to the first point, the program will print a message: INVALID POINT SELECT, REJECTED.

     MOVE CURVE

     This function allows the user to move a selected curve. Once this option is selected, the input box for DX, DY and DZ will be activated. The user can enter any motion vector value relative to the global X, Y and Z directions, then click on the middle mouse button or APPLY button to confirm.

     MOVE POINT

     This function enables the user to move the selected point on line. Once this option is selected, SELECT POINT button and two check boxes are activated, as shown in Figure 5.1.26. Toggle on MOVE DISTANCE option and USER DEFINE option to define the moving direction. Please refer to Section 5.1.4  Shortest Curve for details on USER DEFINE. The user can select point on line directly by cursor or click SELECT POINT button to select a point on line. Click the left mouse button to input the specified distance in the input box for MOVE DISTANCE. Press ENTER button to confirm. Click APPLY to edit.

Figure 5.1.26  Move point on curve

     REMOVE POINT

     This function enables the user to remove point on the selected line. Once this option is selected, the Select Point button is activated. The user can select points on line or click on the middle mouse button to delete the selected points.

2.         MORPHING

     This function allows the user to modify lines by morphing. There are four methods in Morphing function. Figure 5.1.27 illustrates the features and results of various morphing methods.

Figure 5.1.27  Morphing Methods

     NO CONSTRAINT: There is no constraint imposed on the line when it is morphed. The morphed shape will assume a natural spline curve. Refer to type 1 as illustrated in Figure 5.1.27 for the shape of line after morphing.

     KEEP C ANGLE: The tangent at the control point on the line is constrained. The morphed shape will maintain the original tangent direction at the control point of the line. Refer to type 2 as illustrated in Figure 5.1.27 for the shape of line after morphing.

     KEEP E ANGLE: The tangent at both end points on the line is constrained. The morphed shape will maintain the original tangent direction at the end points of the line. Refer to type 3 as illustrated in Figure 5.1.27 for the shape of line after morphing.

KEEP CONVEX: Maintain the convex edge by changing the curvature of the line. Refer to type 4 as illustrated in Figure 5.1.27 for the shape of line after morphing.

 

Figure 5.1.28 illustrates the dialog box of the MORPHING function. Click on the SELECT MORPHING POINT to select the control point. eta/DYNAFORM will highlight the points on the line and request the user to select one control point. A vector is plotted at the morphing point to indicate the morphing direction. The user may move the cursor to see the new shape of the line in real time. Click on the RIGHT MOUSE BUTTON to accept the morphed shape. Click on the APPLY button to update the morphed line automatically. eta/DYNAFORM calculates a default morphing direction that is normal to the line. The user may click on the USER DEFINE option to enter the desirable vector for the morphing direction. Please refer to Section 5.1.4  Shortest Curve for details on USER DEFINE.

Figure 5.1.28  Morphing Curve

3.        SMOOTH

This function enables the user to smooth the selected lines, as shown in Figure 5.1.29. There are four methods that can be used to smooth lines.

Figure 5.1.29  Smooth Curve

AUTO SMOOTH: If this function is toggled ON, the program will automatically smooth the selected section line.

 

MANUAL SMOOTH: If this function is toggled on, the slider and SELECT FIXED POINT button will be activated.

The user can enter any value between 0 and 1.0 in the input field next to the slider as the smooth coefficient and click on the APPLY button to smooth the curve. The user can also drag the slider to smooth the curve in dynamic mode. eta/DYNAFORM will dynamically display the smoothed curve as the slider is dragged, while simultaneously updates the smooth coefficient next to the slider. Click on SELECT FIXED POINT to select control point(s) on the curve. These fixed points remain unchanged during smoothing.

 

THROUGH FIXED POINTS: When this function is toggled ON, the SELECT FIXED POINT button will be activated. Click on the SELECT FIXED POINT button to select control point on curve. A new spline curve passing through the selected fixed point(s) will be created.

 

STRAIGHT SEGMENT: When this function is toggled ON, the Select Segment button will be activated, as shown in Figure 5.1.30. The user can select two points on the selected   curve directly by cursor or click on SELECT SEGMENT button and then select point by cursor. The curve between two points will be smoothed to be a straight segment. Click the middle mouse button or Apply button to confirm.

Figure 5.1.30  Straight Segment

4.         SIMPLIFY

This function is used to simplify the selected line by reducing the number of points on curve. The dialog box is illustrated in Figure 5.1.31.

TOL

The criteria used to simplify the curve. If the chord height of the three adjacent points is less than the defined tolerance, the middle point will be removed from the curve.

 

PREVIEW

Preview the change of points after simplify operation.

 

RESELECT CURVE

This function enables the user to select another line to simplify.

APPLY

Accept the operation without exiting the dialog box..

 

OK

Accept the operation and dismiss the dialog box.

 

CANCEL

Abort the operation and dismiss the dialog box.

Figure 5.1.31  Simplify Curve